Usually, the dispenser head, in which are housed the means that permit the suction of the liquid and its outside dispensing, when operated by the trigger, is connected to the neck of the container by screwing up.
This connection system is of very simple construction and the most widespread in the sector.
Nevertheless, above all during transport operations, the dispenser device is subject to repeated vibrations and sometimes occasional knocks; these external factors affect the screwing up in the sense that they cause its release.
This fact is particularly undesired, due to the consequent loss of liquid contained in the device.
An example of a dispensing device with an head suitable to idly rotate on a container is disclosed in EP-A-0097094; anyway, the joining system disclosed in such document has an high uncertainty on repeatability of the results.